sin(30°+a)-cos(60°+a))/(sin(30°+a)+cos(60°+a)=(sin30cosa+cos30°sina)-(cos60°cosa-sin60°sina)\(sin30cosa+cos30°sina)+(cos60°cosa-sin60°sina)=(1/2cosa+ <var>\frac{\sqrt{3}}{2} <var>sina</var></var>)-(1/2cosa- <var>\frac{\sqrt{3}}{2}</var> sina)\(1/2cosa+ <var>\frac{\sqrt3}{2} sina)+(1/2cosa- <var>\frac{\sqrt3}{2} sina)= \sqrt{3} sina\cosa=<var><var> \sqrt{3}</var></var>tg<var><var>a</var></var></var></var>
Log4(2-x)=log4(25)/log4(16)
log4(2-x)=log4(25)/2
log4(2-x)=1/2log4(25)
log4(2-x)=log4(25)^1/2
log4(2-x)=log4(5)
2-x=5
x=-3
Ответ: -3.
Sin^4=sin^2*sin^2=(1-cos^2)(1-cos^2)=(1-cos)(1+cos)(1-cos)(1+cos)
Решение во вложении......